Obrazy na stronie

Arago's Rotation.


May 2, 1879. margin of the dark space becomes concentrated at the position horizontally being communicated by the other concave side of the cup to a luminous focus, and widenswire. The pencil of the operator has two light“ contact out at the convex side. On further exhaustion, the dark rods "jointed to it, and one of these slides over the edges space on the convex side touches the glass, when positive of a series of "contact plates," having various resistances rotation takes place.

interposed between them and the line wire, while the . 3. Green Phosphorescent Light of Molecular Impact. other rod slides over a second set of such plates connected At very high exhaustions the dark space becomes so large to the other line wire ; at the receiving end of the line that it fills the tube, and when German glass is used the each of these wires actuates its own needle. The two sides are beautifully illuminated with a greenish yellow needles (which are placed at right angles to each other, phosphorescent light.

and are provided with light springs) actuate one writing 4. Projection of Molecular Shadows.-The rays exciting pen, so that the pen moves up or down, and backwards or this green phosphorescence will not turn a corner in the forwards, in exad obedience to the motions of the pencil slightest degree, but radiate from the negative pole in in the hand of the operator at the distant station. Borii straight lines, casting strong and sharply-defined shadows the paper written upon in pencil by the operator at the from objects which happen to be in their path. The best sending station and that written upon in ink by him at and sharpest shadows are cast by fat disks, and not by the receiving station move along as the writing proceeds, narrow-pointed poles; no green light is seen in the shadow and the messages have only to be cut off from time to itself, no matter how thin, or whatever may be the sub-time, wound round a piece of card and sent out to their stance from which it is thrown.

destination, or put into an envelope and dispatched. 5. Magnetic Deflection of the Trajectory of Molécules. In the Meeting. Room Edison's Loud-speaking Tele-The stream of molecules, whose impact on the glass is phone was exhibited by Mr. Arnold White and Mr. C. P. accompanied by evolution of light, is very sensitive to Edison. magnetic influence, and the shadow can be deflected by | Messrs. Preece and Stroh exhibited a synthetic curve bringing a small permanent magnet near, the amount of machine, and frame of curves produced thereby. Autodefiection of the stream of molecules being in proportion matic phonograph. Electro - magnetic vowel-sounder. to the magnetic power employed. The trajectory of the Stereoscopic curves. Synthetic sounder and syren. inolecules forming the shadow is curved when under Phonautograph. magnetic influence.

Mr. J. Browning exhibited a diffraction spe&roscope. 6. Focus of Heat of Molecular Impact.-Great heat is | Automatic spectroscope. Mayall's automatic spectroscope evolved when the concentrated focus of molecular rays with very dense glass prisms. · Automatic sunlight refrom a nearly hemispherical aluminium cup is allowed to corder. New bisulphide of carbon prisms. New automafall on a strip of platinum-foil, the heat sometimes ex. tic electric lamp; burns equally well horizontally or verticeeding the melting point of platinum.

cally. 7. Mechanical Action of Projected Molecules.-An actual Mr. A. Hilger exhibited a quartz spectroscope for the material blow is given by the impinging molecules. A ultra-violet rays : constructed for the Scientific Society at small vaned wheel being used as an indicator, by appro Stettin under direction of Dr. Schönn. Universal Christie priate means the molecular shadow of an aluminium platehalf-prism spectroscope. New spectroscope, devised by is projected on the vanes. When entirely in the shadow Professors Liveing and Dewar. Thollon high-power disthe indicator does not move, but when the molecular persion bottle prism. Hilger's universal variable power stream is defccted so that one-half of the wheel is exposed prism, from 29 to 10°; colleaion of different power prisms to molecular impact it rotates with extreme velocity. and pocket spectroscopes ; (A to H) dispersion.

8. Phosphorogenic Properties of the Molecular Stream. | Messrs. Tisley and Co. exhibited Tisley's dynamo. -Substances known to be phosphorescent under ordinary magneto machine, with single wire on armature : the al. circumstances shine with great splendour when subjected ternate currents are used to augment the magnetism and to the negative discharge in a high vacuum.

for external work; the armature being hollow is kepticool (a.) Becquerel's Luminous Sulphide of Calcium shines by a stream of water flowing through. Donkin's harmo. with a bright blue-violet light, and when on a surface of nograph with parallel and ređangular motions, several square inches is sufficient to faintly light a room.

(6.) The Diamond is very phosphorescent. Most dia. monds from South Africa phosphoresce with a blue light. Diamonds from other localities shine with different colours,

PROCEEDINGS OF SOCIETIES. such as bright blue, apricot, pale blue, red, yellowish green, orange, and pale green. One large fluorescent dia. mond gives almost as much light as a candle when phos

PHYSICAL SOCIETY. phorescing in a good vacuum.

Ordinary Mecting, April 26, 1879. (c.) The Ruby glows with a rich full red, and it is of little consequence what degree of colour the stone possesses Prof. W. G. Adams, President, in the Chair. naturally, the colour of the phosphorescence is nearly the same in all cases.

MR. C. V. Boys gave an account of some experiments In another room Prof. Guthrie, F.R.S., exhibited Broken made by Dr. Guthrie and himsell on the subject of Arago's Glass in Frames, illustrating the Fracture of Colloids. rotation. The experinients were begun with a view to

In Room V. great interest was taken in the working of determine if the drag on a copper disk when a magnet is the Writing Telegraph, exhibited by Mr. E. A. Cowper. made to revolve beneath it, or on the magnet is the disk The object attamed by this instrument is that it enables is made to revolve above it, could be made use of for the operator to write at a distant station miny miles determining the velocity of running machinery. They away, just as though he were present there himself, with made the magnet revolve and obtained the angle of out requiring the use of any special signals, codes, or deflection of a disk suspended by a torsion thread (the signs (10 spell each letter as is now the practice), and hair spring of a watch.) They found, as Snow Harris without the assistance of any person to translate the and others found before, that other things being equal, the signals as received. The instrument acts upon the simple drag is directly proportional to the speed, so that if the principle of communicating at all times, to the writing torsion of the thread could be relied on, and the strength pen at the receiving end of the line, the exact position of of the magnet did not change, a perfe&t velocimeter could the pencil of the operator at the sending station through be constructed. They consider that this method is better two line wires, or, so to speak, giving the latitude and than observing the defledion of a magnet over a revolv; • ongitude of the pencil continually, the position of the ing disk, as in this case they are linițed to less than a pencil vertically being communicated by one wire, and the right angle, and changes in the absolute magnetism of


the earth would affect the results. They also determined Dr. THOMPSON next wrote on a saw blade with a magnet, the effect of change of distance, thickness, diameter, and and dusted iron filings on it, which arranged themselves nature of the disk, &c., their results agreeing with those so as to trace the writing. This is usually shown on a of former experimenters. They observed that the effect steel plate, but a saw retains the virtue for six or eight of concentric circular cuts was far greater than that of months. A modification of this experiment due to himself even many radial cuts; and that when radial seđors consisted in writing on the blade with one pole of a were entirely separated from each other the effect was powerful battery, the other pole being connected to the much less than when these were united at the centre. end of the blade. , They then experimented on liquids by suspending a sphere The third “note" recommended the use of fine steel or cylinder of the liquid between the poles of a revolving fibres, got by breaking iron gauze of 32 meshes to the . electro-magnet, and succeeded in getting a decided and I inch, instead of iron filings for exhibiting magnetic lines. measurable effect. The importance of this is very great, | The fourth note showed that the lines of force got by for they have thus a means of determining the conduc- ! filings fixed on cards are magnetic, that of a magnet tivity of liquid electrolytes by currents induced in the acting as a magnet. The fifth note explained that solid liquid without the use of electrodes and without polari. ( magnetic “figures” could be got by coating iron filings sation.

in shellac to make them light, and floating them in water, Dr. Guthrie stated that as the push on the liquid is or by mixing filings in a soft paste of plaster-of-paris, directly proportional to the current quantity they hope to which could be cut into sections on hardening. measure the conductivities of liquids, and connect these to the conduđivity of solids through the intervention of mercury. In reply to Prof. Adams,

Mr. Boys said that the angle of deflection of the con.
ductor had proved to be proportional to its conductivity.
Dr. O. J. Lodge suggested that the conductivity of the

disks used in these experiments should be determined by
plotting out the equipotential surfaces.

To the Editor of the Chemical News. Dr. SYLVINUS THOMPSON recommended trying conducting jellies in these experiments, and

Sir,-Will you allow me, as a reader of your esteemed Dr. GUTHRIE replied that such were being prepared |

journal, the CHEMICAL News, to address a few lines to for trial, including the permanent jelly made by dissolving

you concerning an article contained in vol. xxxix., p. 160. gelatine in anhydrous glycerine at 100°.

The article in question which attracted my attention is Prof. SYLVANUS THOMPSON then communicated five

that of Mr. M. Benjamin, "On some New Forms of Appalaboratory notes from University College, Bristol.

ratus," a water bottle and a burette clamp. I am asto

The first related to the source of sound in the Bell telephone

nished to see these apparatus described with the predicate receiver. Two theories are now being discussed as to

of new ones; as when I began my studies as a chemist in this effect, the molar theory regards the motion of the

the year 1871 they were quite usual things in the eyes of

my fellow students. In a great many laboratories this diaphragm in mass as the source of sound: the molecular theory finds it in the molecular motions of the magnetic

water-bottle is adopted; I only mention the laboratories core of the instrument. Prof. Thompson applied his l

of the Universities of Leipzig, Bonn, and that of the new method of getting magnetic curves with iron filings dusted

Polytechnische Schule of Dresden. But this the distant on gummed glass to this problem. He found that when

describer may possibly not know ; I therefore draw his no currents passed in the telephone the magnetic lines

attention to the Zeitschrift für Analytische Chemie, by springing from the pole of the magnet are gathered toge.

Fresenius, where he will find, Vol. II., page 190, from the ther on the diaphragm opposite, over a central region,

year 1872, this recently devised apparatus described by which is magnetised lamellarly, or like a magnetic shell.

H. Fresenius. This description is illustrated by a wood. The rim of the plate beyond this region is, however,

cut, which differs from the one in the CHEMICAL News by magnetised radially, and between these two zones there

only showing the chief parts, the tube through which the is a neutral circle. It was remarkable, too, that the lines

water flows and fills ihe bath to a height, which is deterof force touching the plate were bent back around the

mined by a vertical tube through which an excess of water circle, forming a kind of valley. When the current passed

is allowed to flow out. The bath itself is left out in the in the coil in a direction so as to reinforce the magnetism,

woodcut, but this may, with very little imagination, easily the lines are gathered more closely on the central region

be added. As to the other new apparatus spoken of in of the plate. If the current diminishes the magnetism

Mr. Benja nin's essay, I will only mention, in a few words, the lines are, on the other hand, repelled from the plate.

that this is just as old as the first, and even older. It is, The neutral line is also altered. In the first case it

and was, to be found in the catalogues of every business shrinks in size, in the second it expands. A small thick

of chemical apparatus of some significance, such as disk is wholly magnetised lamellarly; a disk entirely

Lezbold, Cöln, Gehrhardt, Bonn, Noellner, Darmstadt,

and I do not doubt that it also is to be found in English magnetised radially becomes slightly conical in shape. In the actual telephone the disk is flat at the middle and

and American businesses.-I am, &c., conical at the edges. As the neutral ring shifts the

DR. FERDINAND KORN. diaphragm will assume new nodal lines. Dr. Thompson

Renteria, April 16, 1879.

Guiyuzcoa Espana. concludes that the molecular theory is nut, therefore, necessary to account for the speech of the telephone, although it may assist. As confirming this view he found LOSS OF NITRE IN VITRIOL MANUFACTURE. that with iron rings round a cardboard diaphragm and an iron centre piece the enunciation was good, though the

To the Editor of the Chemical News. timbre was altered; whereas with radial pieces of iron on the cardboard the timbre was good, but the enuncia. Sir, I should have thought, from Dr. Hurter's last reply tion bad. In reply to Prof. Adams, Dr. Thompson said to me in Dingler's Fournal and for other reasons, that he that the stronger the magnet the smaller the lamellarly | would not renew the discussion upon the loss of nitre, at magnetised space became, and that with a thicker disk least upon precisely the same lines as those previously the neutral ring was not so well marked.

taken. “But as he thinks fit so to do, and this time before Dr. LODGE suggested that the best place for the coil the English public, I am simply compelled to reply to him would be in the valley over the neutral ring, which was

once more. Those who are further interested in this matter in an unstable condition.

I refer to my explicit refutations of Dr. Hurter's views and


Loss of Nitre in Vitriol Manufacture.

J CHEMICAL News, 1 May 2, 1879.

statements in Dingler's Journal, vol. ccxxviii., pp. 70, 152, 1 exaggeration, at 25 per cent of the nitre ; and he declines and 548.

to admit any“chemical loss” other than that taking place The principal reason why I have always contended that in the Glover-tower or in the chambers. Consequently, in the Glover tower no appreciable loss of nitre takes place in factories working without a Glover-tower, the total loss is this :- That notoriously since the introduction of that of nitre could only be 25 per cent of that assumed as the apparatus the consumption of nitre in vitriol works, every basis of his calculations, viz., 4 parts per 100 of sulphur, thing else being equal, has not merely been found to be no that is, I part per 100 of sulphur. To this could only be larger than before it has actually decreased, and, in some added the amount of nitre lost in the chamber-acid over cases, considerably. For instance, it fell from 20 to 13 and above the 10 per cent allowed for already in the above parts of nitre to 100 parts of pyrites, according to the 25 per cent. Mr. Davis found 8.7 and 3:6 per cent of the figures furnished to me by the manager of one of the best nitre in undenitrated chamber-acid (leaving out the “ only French works, and the fact of that decrease having taken occasionally watched” cases). Dr. Hurier's own stateplace is not disputed by Dr. Hurter himself in his German ments in Dingler's Journal are no use to us here ; for papers. But "all fear of appreciable loss of nitre in the they refer to works where, in the first instance, altogether Glover tower has vanished now," at any rate, among the too much nitre was lost (5 per cent of the sulphur), and general body of vitriol makers, although Dr. Hurter, and where, secondly, the very existence of a Glover-tower and possibly a few others, take exception to that view. This the possibility of denitrating the chamber-acid, would, I can positively affirm from numerous verbal and written quite properly, cause this to be kept rather more nitrous communications of vitriol makers in all principal countries than where the Guy-Lussac acid is denitrated by steam, (whom, if need be, I could quote by name); and the fact and all the nitre contained in the chamber-acid is lost. adduced in my last letter, viz., that some of the most care The only statements referring to the latter case upon which ful manufacturers (e.g., Schaffner of Aussig) introduce all I can lay my hands are the following:-Kolb (Bull. Soc. their nitric acid through the Glover tower is a striking Muhl., 1872, p. 309) states the percentage of N203 in the proof of the above. Indeed, the all but universal use of “large chamber" (that from which the vitriol is withdrawn the Glover tower is the best practical refutation of the for use) = O'oro per cent, the acid containing 58.6 per cent reproach cast upon it by Dr. Hurter, and before him by SO,Hz. This is equal to 0'046 N2Oz, or o 100 NaNoz M. Verster. It therefore requires very w ighty and accu upon 100 sulphur. 'He does not state the amount of nitre rately defined arguments to substantiate the statement used, but we may safely assume it at least = 4 per cent of that an appreciable, let alone a large, loss of nitre takes the sulphur, and thus we arrive at only 24 per cent of the place in the Glover tower. Has Dr. Hurter produced any total nitre as lost in the chamber-acid. arguments of that kind ? He estimates the loss of nitre Hasenbach (Ber, der Deutsch. Chem. Ges., vii., p. 681) in the manufacture of vitriol from various sources, and lays arrives at a loss of 31 cwts. of nitrate for 60,000 cwts. of the unaccounted-for balance to the charge of the Glover vitriol of 66° Baumé, which he states to be about 6 per tower. It is unnecessary to say how little conclusive such cent of the total nitre used (it is about o.19 nitre to 100 a reasoning process is, for the result is only a margin, sulphur). arrived at indirectly, and is vitiated by all the errors in Scheurer-Kestner (Comptes Rendus, November, 1875), estimating the remaining possible sources of loss. It could in order to save his platinum stills, keeps his chamberonly be admitted if the latter estimation was in all cases acid rather sulphurous, and thus practically quite free based upon thoroughly reliable data.

from nitre ; but he has himself stated that his consumption For argument's sake, and as I am extremely unwilling of nitric acid (at 36° Baumé) is 3 per cent of the pyrites, to open out any side issue, I will grant Dr. Hurter's state equal to about 407 nitre to 100 sulphur. Consequentiy, if ment of the mechanical losses,” amounting to 25 per we allow io per cent of the nitre as lost in the chamber. cent of the nitre, or i part of nitre to ino sulphur.

acid, also for works without a Glover-tower, we are very Coming to the chemical losses," Dr. Hurter declines much on the right side, according to all authorities. Now to admit any loss of nitre by the oxidation of arsenious this brings our total possible loss, apart from that in the acid in the Gay-Lussac tower. Here he is at variance, chambers themselves, for works denitrating by steam, to not merely with the statements of Davis, but also with the 25 per cent, leaving 75 per cent of the loss to take place in very careful investigation of H. Hjelt (Dingler's Journal, the chambers themselues (whether by Weber's reaction or vol. ccxxvi., p. 174). Nor can I agree with him that nitric l in any other way), not 20 per cent, as allowed by Dr. oxide cannot escape as such, on the ground that it would Hurter. Thus the big margin claimed by him as chemical be re-converted into higher oxides by the excess of oxygen loss in the Glover-tower suddenly vanishes into thin air. present. That nitric oxide sometimes does occur in the I should be the last person in the world wishful to "put exit-gas, even when working under normal conditions, i.e.,

.bu. I a manufacturer off his guard” and “prevent further with an excess of oxygen, is proved by the ruddy vapours

search" by my statements. But I cannot certainly, on which are formed at the mouth of the chimney, although the " sight" in the exit-pipe is altogether colourless. This

the other hand, run to the opposite extreme, and decline is easily explained by the fact that there is not time for

to accept the fact that hitherto no satisfactory proof has the gases to be thoroughly mixed during their rapid transit

been given for any loss of nitre occurring in the Glover.

tower, and that all unbiassed evidence goes the other through the tower, so that in some places free oxygen, and in others NO, may be present.

way.--I am, &c.,

George LUNGE. But now I come to Dr. Hurter's principal fallacy. This

Technical Laboratory of the is the assumption that the “chemical loss” in the chamol Federal Polytechnic School, Zürich. bers themselves does not exceed 20 per cent of the nitre introduced into the system. But this is the very point to be proved, and such a proof is not even attempted by Dr. Hurter, otherwise than by quoting from Mr. Davis, to The Wax of Ficus Gummiflua.-F. Kessel-This whose paper in every other respect he denies any demon- wax is a chocolate-coloured mass, which softens when strative power. But here he should most assuredly have heated and melts between 60° and 70°. Boiling water maintained his denial with all jealousy; for from Mr. extracts a considerable quantity of a brown colouring Davis's position it might be inferred that in factories matter, leaving the wax nearly white. Boiling alcohol making their acid from brimstone, and working with a dissolves considerable quantities of the wax, which on nitre-recovery apparatus, next to no loss of nitre should cooling are re-deposited in a white mass resembling take place, as they have not to contend with arsenic ! But cauliflower. By treatment with ether the wax may be here I am able, as I was in my German papers, to turn separated into two bodies more or less soluble, the former Dr. Hurter's own arguments against himself. He states having the composition CisH300 and the latter C2H560. the "mechanical losses," and that, as he thinks, with great i-Ber, der Deutsch, Chem. Gesell.


May 2, 1879.)
Chemical Notices from Foreign Sources.

195 CHEMICAL NOTICES FROM FOREJGN L. Formation of Carbonic Acid, Alcohol, and Acetic

Acid in the Presence and Absence of Alcohol.SOURCES.

A. Béchamp.-The same products are generated in either case.

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NOTE.-All degrees of temperature are Centigrade, unless otherwise Berichte der Deutschen Chemischen Gesellschaft su Berlin, expressed,

No. 17, 1879.

Reductive Action of Milk-sugar upon Alkaline Comptes Rendus Hebdomadaires des Séances, l'Académie de Solution of Copper.-H. Rodewald and B. Tollens.des Sciences. No. 13, March 31, 1879.

The authors point out that whilst chemists are agreed on Conformity of the Systems of Fraaures Obtained

the reductive power of dextrose, there is great discrepancy Experimentally with the Systems of Joints Inter

concerning lactose, i mol. of which is considered to seding the Cliffs of Normandy.-M. Daubrée.--In

represent various quantities of copper oxide, ranging from general these joints form two systems, one of which 6% to 8 atoms. They find that the exact quantity recorresponds to the direction, and the other to the line of quired is 7:47 atoms of copper to i mol. of milk-sugar, the greatest slope.

=6.700 mg. milk-sugar to i c.c. of Fehling's liquor. Convenience of Special Denominations for Dif.

They recommend that this reagent should not be prepared ferent Orders of Fractures of the Crust of the Earlh.

| in quantities beforehand ; 60 grms. of the best caustic -M. Daubrée.-The joints, or as he suggests, disjoints,

soda and 173 grms. of re-crystallised tartrate of potash due to rupture, the author would call diaclases. When

and soda are dissolved in litre of water, whilst the fracture is accompanied by displacement he terms it

34.639 grms. pure copper sulphate are dissolved separately paraclase, whilst as a common name for both he suggests

in another half litre." Equal volumes of these two liquids

are mixed when wanted. litho-clase. Chemical Researches on a Filamentous Matter

Oxidation of Xylol-sulphamids.-Ira Remsen.-A found in the Excavations at Pompeii.-S. de Luca.

reply to a communication by O. Jacobsen, which the The filaments in question seem to be carbonised fibres of

author characterises as “ almost purely personal.” flax or hemp, and had probably been collected for lint.

Formation of Ethylamin.-H. Kähler.-1f the black Thermic and Galvanometric Laws of the Electric heated in a glass tube, through which a current of dry ethyl

powder produced by agitating calomel with ammonia is Spark Produced in Gases.-E. Villari.—The heat chloride is passed, a small quantity of ethylamin is prodeveloped in gases by an electric spark is proportional | duced. to the quantity of electricity which produces it. The Certain Colouring Matters of the Rosanilin Group. galvanometric deviations produced by the discharge of - E. Fischer and O. Fischer.-If a solution of dimethyl. Leyden jars are proportional to the quantities of electri. anilin in dilute sulphuric acid is mixed with manganese city condensed. The galvanometric deviations produced the formation of violet derivatives begins at 30° to 40°. by one and the same charge of the condensers are constant and independent of the length of the spark produced

Meta-nitro-phenol and its Derivatives.--A. Bautlin. at any given point of the circuit. If one and the same abstraie

-An interesting paper, but not susceptible of useful

abstraction. quantity of electricity amassed in any condenser is discharged through a metallic circuit, interrupted so as

Certain Greek Tanning Materials.-Hans Jahn. to give rise to a spark, the quantity of electricity brought The author states the average proportion of tannin in into play in the discharge is constant and independent of the cups of valonias, freed from scales at 22.615 per cent, the length of the spark. The quantity of heat developed in the suales at 36.60, and in the entire ware at 33 per in any gas by the electric spark increases in proportion to cent. Peloponesian gall-nuts contain on an avera, e its length, whence the temperature of the spark at its 47:6 per cent of tannin: pine bark from Crete 9810 per different points is independent of its length, and the

ore is independent of its length. and the cent, and from Asia Minor 17'285 per cent. electric resistance of the gases is proportional to the

Behaviour of Mono- and Dibrom-acetic Ethyl thickness of the gaseous layer traversed by the discharge. I ethers with Aqueous Ammonia.-F. Kessel. The When the charge producing the spark remains the same author sought to use the behaviour of these bodies with the quantity of heat developed by this spark is independent aqueous ammonia as a means for their separation, but of the surface of the condenser. In fine, the thermic and succeeded only when the dibrom-acetic ether formed the galvanometric deviations produced, the former by the greater part of the mixture. spark and the latter by the discharge of a condenser, are proportional to the quantity of electricity which produces

Etherification of Secondary Alcohols.-N. Men

schutkin.-Not suitable for abstraction. them, and at the same time to the length of their active circuits (this name being applied either to the length of

Cantharic Acid and a Terpenoid Hydrocarbon.the spark or to the length of the galvanometric wire).

| J. Piccard.-Cantharic acid is a powerful mono-basic acid.

The author describes the copper and potassium salts, and Magnetic Rotatory Power of Gases at Ordinary the origin of cantharen, which he considers as formed Pressure and Temperature.-H. Becquerel.-By means from cantharic acid by the abscission of carbonic acid. of a special arrangement which the author describes he Gelatinous Silicic Acid and an Inorganic Memhas not merely succeeded in showing the magnetic rota- brane.-E. Ullik.The author has found it possible to tion of the plane of polarisation of light at the ordinary temperature and pressure, but has been able to measure it

wash the well-known jelly produced by pouring dilute

solution of soluble glass into hydrochloric acid and with precision.

allowing the mixture to stand. He treats the mass roRotatory Magnetic Power of Vapours.-E. Bichat. peatedly with water, taking care not to break it up, and -On causing the current of eighty large Bunsen elements has obtained it free from hydrochloric acid and chlorides, to act upon a.ray of polarised light traversing vapours of and in the formation of membrane-like layers, which, carbon sulphide the author has obtained an evident but though incapable of filtering, are capable of dialysing like slight deviation of the plane of polarisation.

an animal membrane. Pressure Exerted by Galvanic Deposits.—M Bouty. Contributions to the Voluminar and Steric Law.-Not suitable for abstraction.

H. Schroeder.-Incapable of abstraction. Alkaloids of the Pomegranate.--C. Tanret.--The Adion of Potassium Cyanate upon Epichlorhydrin. author finds that pelletierin is accompanied by three -A. L. Thomsen.-The reaction consists in the addition other volatile bases, the extraction of which he describes, of i mol. cyanic acid 10 i mol. epichlorhydrin,


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Chemical Notices from Foreign Sources.


1 May 2, 1879. Bulletin de la Société Chimique de Paris,

Iron and Steel Institute.-Thé Annual Meeting of the No. 6, March 20, 1879.

Iron and Steel Institute will be held on May 7, 8, and 9, Determination of the Total Nitrogen in Manures.

at the Institution of the Civil Engineers. The programme -A. Rémont.--The author, referring to the well-known

includes papers and discussions on :-" The Mechanical fact that when a manure contains nitrates the determina.

Properties of Iron and Mild Steel," by Mr. D. Adamson, tion of its total nitrogen is impossible, recommends to add

C.E. “On the Use of Steel in Naval Construction," by to the portion taken for analysis powdered white sugar to

Mr. Nathaniel Barnaby, C.B., H.M.'s Chief Constructor. the extent of ten times the quantity of the nitiates

“On the Use of Steel in the Construction of Bridges," by supposed to be present, basing this approximation on the

Mr. H. N. Maynard. “On the Elimination of Phos. proportion of soluble matters which the manure contains.

phorus in the Bessemer Converter," by Mr. Sidney G. (If the manure contains soluble phosphates, salts of potas.

Thomas, F.C.S., and Mr. Percy C. Gilchrist, A.R.S.M., sium, &c., the total soluble maiter can throw no definite

F.C.S. “On the Removal of Phosphorus and Sulphur light on the quantity of nitrates which may be present.)

during the Bessemer and Siemens-Martin Processes of The author adds the somewhat needless precaution that Steel Manufacture," by

Steel Manufacture," by Mr. G. J. Snelus, F.C.S., &c. the sugared sample must be mixed with soda-lime before “On a New Volumetric

| “On a New Volumetric Method of Determining Man. introduction into the combustion - tube lest detonation ganese in Manganiferous Iron Ores, Spiegeleisen, Steel, occur on heating.

&c.," by Mr. John Pattinson, F.I.C., Newcastle-on-Tyne.

" On a Ready Means of Moulding Lime, and Making Production of Crystalline Chromate of Baryta.

Lime or Basic Bricks and Linings for Furnace Converters, Leon Bourgeois.-Already noticed.

&c.," by Mr. Edward Riley, F.C.S., F.I.C., &c. "On a Certain Hydrocarbides formed by the Action of

Practical Combination of the Bessemer and Puddling Methylic Chloride upon Toluen in Presence of Alu. Processes," by Mr. Edwin Pettitt, Cheltenham. “On the minic Chloride.-E. Ador and A. Rillet.--This memoir Results of Working the Godfrey-Howson Furnaces at the does not admit of useful abstraction.

Works of Tamaris, Gard, France,” by M. Escalle. “On Bromo-citraconic Acid.-Edme Bourgoin.—This acid, the Chemistry of Puddling," by Mr. H. Louis, A.R.S.M., C10H6Br2O3, is bibasic, yielding alkaline and earthy Londonderry, Nova Scotia. "On a New Process for alkaline salts of little stability and readily soluble in water. Protecting Iron and Steel against Rust,” by Prof. Barff.

Relative Affinities and the Reciprocal Displacements of Oxygen and the Halogens.-M. Berthelot. -The author proposes to show that the reciprocal dis.

NOTES AND QUERIES. placements between the halogens and oxygen, united either with the metals or the non-metallic elements, may Insurance of Tar Distilleries (Reply to W.A. R.).-Though be predicted according to the sign of the quantities of heat not able to speak positively of the present time, I can certainly aver liberated in the formation of the compounds which these tha

that a few years ago it was quite impossible to find any fire insurance

office willing to grant the protection desired. I think it bigbly elements form with oxygen on the one hand, and with the

probable that the same state of things still exists, and, what is more, halogens on the other.

is extremely likely to do so. The tar distiller's best plan is to see to

it that he sets such of his plant and materials requiring protc&ion Thermo-chemical Researches on Magnesium,

from the weather, under cover of the simplest and least inflammable Calcium, Strontium, and Barium.-J. Thomsen. kind. The tar-stills and other large stills worked with fire usually Along with an increasing atomic weight we find an aug. remain uncovered with any roof. My own experience is that with

careful arrangement of plant, and proper precautions and care, there mentation in-(a.) The stability of the hydrates and the

is little need for fear, and, in case of a fire even, this may, except in heat liberated on the hydration of the oxides. (6.) The very exceptional cases, be quickly subdued without much damage solubility of the hydrates in water and their heat of solu. being done. See communication on "Extinguishing Fires ia Tar tion. (c) The heat of formation of the chlorides, bromides,

Distilleries, &c."-Watson Smith. iodides, and nitrates. On the other hand, with an increasing atomic weight we find a decrease in-(a.) The affinity of the chlorides, bromides, io dides, nitrates, and

MEETINGS FOR THE WEEK. sulphates for water; the proportion of water of crystallisation and the heat liberated on its fixation. (6.) The

ation. (0.) ne | MONDAY, 5th.-Medical, 8.30. (Anniversary.) solubility and heat of solution of the same compounds.

Royal Institution, 5. General Monthly Meeting. The atomic weight bears no relation to-(a.) The heat

Society of Arts, 8. “Recent Advances in Teleof neutralisation of the dissolved hydrates. (6.) The

graphy," by W. H. Preece. (Cantor Lectures.)

TUESDAY, 6th.-Civil Engineers, 8. total heat of formation of the hydrates, i.e., R, O, H20.

Royal Institution, 3. “Schumann," by Mr. Journal f. Praktische Chimie, xvi., p. 67.

Ernst Pauer. Action of Mono-chlor acetic Acid upon the Sulpho.) Wednesday, 7th.-Society of Arts, 8. Å The Government Patent

Zoological, 8.30. cyanates of the Aromatic Monamines.-.J. H. Jæger.

Bilí" by W. Lloyd' Wise, A.I.C.E. -Aniline and toluydin, dissolved in alcohol, have been

THURSDAY, 8th.-Royal, 8.30. treated with mono-chlor-acetic acid along with ammonic

Royal Institution, 3. “Dissociation," by Prof.

Dewar. sulpho-cyanate.- Fourn. f. Prakt. Chemie, xvi., 17.

Royal Society Club, 6.30.

Society of Aris, 8. "The History of Alizarin aod

Allied Colouring Matters, and their Production

from Coal-Tar," by W. H. Perkin, F.R.S. MISCELLANEOUS.

FRIDAY, 9th.-Royal Institution, g. " Habits of Ants," by Sir Joha


Astronomical 9. Mr. W. Valentin, F.C.S.-Mr. W. Valentin, F.C.S.,

Quekett, 8. is about to retire from the Laboratory of the Science SATURDAY, roth.–Royal Institution, 3. “Architecture," by Mr. H.H. Schools, South Kensington, formerly the College of

Statham, Chemistry, in connection with which he has laboured for

Physical, 3. more than twenty years. It would be difficult to find one to whose patient work the present generation of chemists is more indebted, and a few of his old friends and pupils

TO CORRESPONDENTS. of the Royal School of Mines, recognising the value of i his long services, are forming a committee with a view of E. W.-At the Library of the Commissioners of Patents, Southamppresenting him with a testimonial. The Committee

ton Buildings, Chancery Lane, W.C. already includes Dr. Frankland, Dr. Forbes Watson,

E. W. Young.-Such works as “ Watts's Dictionary of Chemistry,"

Ure's Dictionary of Arts, &c.," " Ganot's Physics," Wagner's and Prof. Guthrie, Dr. E. J. Mills, and Mr: W. Chandler. Richardson and Watts's works on Chemical Technology seem tu Roberts.

already supply the information.

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